How much movement? If it isn't a great deal I'd leave it and get it up and running so you can enjoy it as an engine then keep an eye out for another bearing, if it's totally buggered then your choice is already made.

There is a slight up & down movement and I can hear it knock so I assumed that when running it might not sound great but as you say suck it and see until a bearing becomes available out of another engine being broken for spares. George.